Knife construction

ABSTRACT

The knife construction disclosed herein includes a blade, handle tang and hilt composed of different materials which are fusibly joined along their common surfaces employing selected brazing materials and selected brazing and tempering temperatures to produce a nonporous fusion joint of high strength and prolonged longevity.

United States Patent [72] Inventor John N. Cooper Z200 Burbank Blvd"Burbank. Calif. 91506 [2|] Appl. No. 877,550

[22] Filed NOV 20, 1969 Division oi Ser. No. 682,470. Nov. 13. 1967.Pat. No. 3,481,038. [45] Patented July 27, 1971 [54] KNIFE CONSTRUCTION5 Claims, 10 Drawing Figs.

52 use: 76/104 511 lnt.Cl ..B2lkll/00 [50] Field of Search 30/344, 342,295; 76/104 [56] References Cited UNITED STATES PATENTS 689,049 12/1901Hirsch 30/344 X 1,989,225 l/l935 Campbell 30/342 PrimaryExaminer-Bernard Stickney Attorney-Roger A. Marrs ABSTRACT: The knifeconstruction disclosed herein includes a blade, handle tang and hiltcomposed of different materials which are fusibly joined along theircommon surfaces employing selected brazing materials and selectedbrazing and tempering temperatures to produce a nonporous fusion jointof high strength and prolonged longevity.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to knife constructions and, more particularly, to a novelconstruction of this class for joining several separate and distinctcomponent parts of the knife into a unitary construction adapted toreceive extensive abuse while in use without suffering adverse effectsof metal fatigue, loss of finish luster or breakage.

2. Description of the Prior Art In the past, it has been theconventional practice to produce a utility knife such as may be used infishing, hunting, fighting or the like by fabricating the blade andhandle tang from the same blank of metal. Next, the hilt or guard isplaced about the tang at it integral merger with the blade and themating surface of the construction are soldered or welded to form abonded joint. A handle portion is then mounted onto the tang whichcompletes the construction of the knife after the blade has been shapedand the exposed metal portions suitably polished."

Although this common practice results in a generally acceptable knifeconstruction, it has been found that the joint is unsatisfactory sincethe weakest part of the knife is at the joint location where the bladeis integrally formed with the tang. Inasmuch as the tang issubstantially smaller in overall cross-sectional area than thecrosssectional area of the blade, the joint area has a tendency torapidly deteriorate under extensive stress and loading conditions. Forexample, the handle surrounding the tang is grasped by the user and theblade is employed for chopping or cutting operations which places themaximum load at the leverage point defined at the integral joint of thetang with the blade. Such loading has a tendency to forcibly bend atthis critical location until the tang breaks away from the blade.

Furthermore, the welding procedure for fusing the hilt or guard to theblade and tang is generally of a porous nature which permits air andmoisture to combine with the metal to cause corrosion and rust. Aftercontinuous use of the knife, the deterioration further fatigues andweakens the joint at this critical location which results in breakagethereof.

In other constructions, an attempt has been made to avoid the aboveproblems by constructing the blade and handle tang from two separatepieces which are joined together by a threadable connection or othertype of fastening means. Obviously, such a practice is expensive andrequires precision tolerances and additional manufacturing procedureswhich complicate the construction. Furthermore, such a practice does notavoid the adverse efiects of porous construction and materialdeterioration due to exposure to a corrosive environment.

SUMMARY OF THE INVENTION Accordingly, the problems and difficultiesencountered with conventional knife constructions are obviated by thenovel knife construction and method of fabrication of the presentinvention which provides separate components such as the blade, handletang and hilt which are composed of dif ferent materials that are joinedtogether in an integral unitary structure by an eutectic joint havingthe physical characteristic of being nonporous. The base of a metalblank for the blade is formed with a notch adapted to receive the end ofa bolt' intended to comprise the handle tang. The end of the bolt isseated in the notch and welded thereto so that fusion takes place toform an integral joint between the bolt and the blade blank. A hilt isformed with a central hole adapted to be inserted over the bolt andseated adjacent the base of the blade. The hole is countersunk on bothsides of the hilt so as to provide suitable recesses for receivingeutectic material during a brazing procedure which integrally forms thehilt with the bolt and metal blank of the blade. The material disposedin the recesses form fillets which are of nonporous composition andwhich are compatible with the material of the components to provide aeutectic joint which is resistive to corrosive environments.

Preferably, the material of the blade and handle tang is of stainlesssteel while the hilt is composed of bronze material. A handle composedof phenolic micarta may be secured about the handle tang and suitablyshaped to accommodate the hand grasp of the user. The blade blank may besuitably ground to provide a cutting edge and/or a false edge as well asto provide a ricasso adjacent the hilt in the base portion of the blade.After securement of a butt cap on the tang and suitably polishing theexposed metal surfaces, the knife construction is complete and ready foruse.

Therefore, it is among the primary objects of the present invention toprovide a novel knife construction and method of fabricating whichresults in a unitary structure formed by a common eutectic jointintegrally connecting the blade, handle tang and hilt.

Another object of the present invention is to provide a novel knifeconstruction including a nonporous joint integrally forming the blade,handle tang and hilt so as to be resistive to corrosive conditions andwhich exhibits characteristics of high strength.

Still another object of the present invention is to provide a novelknife construction and method of fabrication by which an integral jointis produced at the junction of the hilt, handle tang and base portion ofthe blade by means of brazing techniques and fillet materials effectiveto fuse together at selected temperatures so as to provide a strong bondtherebetween.

Still a further object of the present invention is to provide a BRIEFDESCRIPTION OF THE DRAWING The features of the resent invention whichare believed to be novel are set forth with particularity in theappended claims. The present invention, both as to its organization andmanner of operation, together with further objects and advantagesthereof, may best be understood by reference to the followingdescription, taken in connection with the accompanying drawings, inwhich:

FIG. 1 is a side elevational view of a knife formed from the novelconstruction of the present invention;

FIG. 2 is an exploded view illustrating the component parts of the knifeconstruction preparatory to being integrally joined;

FIG. 3 is a fragmentary view of the handle tang welded to the bladeblank;

FIG. 4 is a top plan view of the welded joint as taken in the directionof arrows 4-4 of FIG. 3.

FlG. 5 is a fragmentary view, partly in section, illustrating thebrazing of the guard or hilt onto the handle tang and base portion ofthe blade at the welded joint;

FIG. 6 is a longitudinal cross-sectional view of the knife constructionshown in FIG. 5 as taken in the direction of arrows 6-6 thereof;

FIG. 7 is a transverse cross-sectional view taken in the direction ofarrows 77 of FIG. 5;

FIG. 8 is an exploded sectional view of the handle portion of the knifeconstruction preparatory to securement of the cap butt and shaping;

FIG. 9 is a side elevational view of the handle portion showing afinished shape; and

FIG. 10 is an end elevational view of the knife construction as taken inthe direction of arrows 10-10 of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a knifeconstruction of the present invention is illustrated in the generaldirection of arrow and the construction represents a finished product.The knife construction includes a blade II, a hilt or guard 12 and ashaped handle 13 terminating in a butt cap 14. The shape of the handlel3 and butt cap 14 are compatible so that the handle may be readilygrasped by the user and the user's hand is protected from the blade bythe hilt 12. The blade includes a ground cutting edge 15 terminating ina point 16 at one end and a ricasso 17 formed in the base portion of theblade adjacent the hilt on the back side of the blade terminating inpoint 16 on one end and terminating midway between the opposite ends ofthe blade along a back 20. A fillet 21 extends between the base portionof the blade and the hilt l2 and is ofa nonporous characteristic. Thefillet 21 is continuous about the knife construction and fusibly joinsthe hilt 2 with the base of the blade 1 l.

Referring now to FIG. 2, the knife construction 10 is initiallyfabricated by providing a blank 22 for the blade which is cut fromsuitable knife stock such as stainless steel. The material is carefullyand skillfully cut to obtain the proper length, width, etc. to becompatible with the overall dimensions of the finished knife. The blankis formed, for example, by grinding to the desired blade outlineconfiguration by removing stock material therefrom. An emory wheel maybe employed for removing the material. The desired blade outline shapemay take the form of an edge 23 representing the knife edge 15, and edge24 which will ultimately be the false edge 18, a cutout 25 for thericasso and a notch 26 formed in the base of the blade blank 22. Thenotch 26 is made in the base end of the blade for subsequent fittingtherewith of a handle tang which takes the form of a bolt 27. The handletang is fonned from a threaded machine bolt and serves as an anchor forthe later addition of the handle itself. A threaded end 28 of the boltwhich is on the opposite end to the end seated in the notch 26 serves toreceive the butt cap of the handle which will be described later.

Another component part of the knife construction resides in the hilt orguard 12 which is preferably composed of bronze material and includes acentral aperture 30 located midway between its opposite ends. Theopposite sides of the hilt 12 are countersunk about the aperture 30 soas to form recesses 31 and 32.

Referring now to FIG. 3, the handle bolt forming tang 27 is shownsecured to the base portion of the blade blank 22 by means of acetylenewelding at a joint 33. An emory wheel is employed to form an angular cuton opposite sides of the joint in the base of the blade as representedby numerals 341 and 35 in preparation to receive the hilt 12 after ithas been shaped. Also, the opposite sides of the joint 33 are ground byan emory wheel to remove excess metal therefrom so that the joint istapered on its opposite sides as shown by numerals 36 and 37 in FIG. 4.

Referring now to FIG. 5, the hilt 12 is formed with a slight curve orarcuate shape so that when the bolt 27 is inserted through the aperture30, the front face of the hilt 12 will substantially coincide with thebase of the blade 22. However, exact surface mating is avoided so that apair of gaps 38 and 40 are provided into which a eutectic material isdisposed so as to form a fusible bond between the blade and the hilt.

In actual practice, the blade, handle tang and the hilt are secured byfirst inserting the hilt aperture over the handle tang and advancing thehilt against the base of the blade. The hilt is fused to the handle tangand the sides of the blade from the bottom, or blade side, using abronze rod and an acetylene torch. Extreme caution must be taken toattain a nonporous weld to prevent pits in the finished exposed surfaceof the hilt. The blade is then held in a vise so that the handle tang isstraight up. The hilt is then finally and completely made a part of thealready joined blade and handle bolt.

As shown iii/FIG. 6, the bronze rod weld is indicated by numerals fl-and 42 which join the front side of the hilt with the blade andconstitutes the fillet 21. The bronze rod material forming the weldoccupies the recess 31 formed in the hilt and partially occupies theaperture 30 surrounding the joint 33. Using a silver brazing rod with atensile strength of approximately 60,000 psi. the hilt 12 is silverbrazed from the rear or handle side so as to occupy the recess 32forming a continuous fillet 43 and 44 on opposite sides of theconstruction. The recesses on both sides of the aperture 30 allowcomplete fusing of blade and tang with the hilt to form an integraljoint.

After suitable cooling the unit is cleaned on a sanding wheel whichremoves excess bronze from the blade side and bolt side of the hilt aswell as from the hilt itself. Next, the blade is operated upon by theemory wheel where approximately percent of the hollow grinding processis accomplished to form the blade edge 15 and false edge 18. However, nomore than 80 percent of the hollow grind can be done at this point sothat blade warpage during the subsequent tempering process is prevented.

Next, the knife construction is placed in a firebrick enclosure and theblade is heated with an acetylene torch to approximately l400F. Again,extreme care is required because of the difference in meltingtemperatures of the metals composing the construction. Throughexperience using color charts of heat treated metal in various stages,it can be readily determined by visual means when the blade has reachedthe desired temperature. Once more, stress must be placed on the carefuluse of the torch at this time to prevent warpage and/or melting throughoverheating or improper tempering through underheating. As soon as theblade has been brought to the proper temperature, the construction isimmediately immersed in a container of suitable quenching oil. Theconstruction is maintained in the oil bath until completely cooled. Atthis time, the blade is extremely hard and brittle and to complete thetempering process, the construction is now placed in an electric ovenand is slowly brought to a temperature of approximately 450 F.thermostatically. The construction is then removed from the oven andallowed to cool at room temperature. At this time, a completely temperedconstruction is provided.

Referring now to FIG. 8, the handle 13 and butt cap 14 are initiallymade in rough form. The handle is composed of oblong-shaped phenolicmicarta blocks 4549 inclusive, of varying thicknesses depending upon thedesired ultimate design. Each block is then drilled to provide a holeadapted to receive the handle tang. Each hole is provided with acountersink on the opposite openings of the hole from each side of theblock to facilitate assembly of the blocks. The butt cap is fashionedfrom east brass and is drilled on one side with a threaded hole 50adapted to threadably mate with the end 28 of the handle tang.

Each micarta block is placed separately on the handle tang and secured.The block 45 is secured to the hilt and subsequent blocks, if used, aresecured one on top of the other. Bonding of the blocks is achievedthrough the use of a suitable industrial epoxy cement. The doublecountersinks permit the use of additional cement over a larger area ofcoverage so as to guarantee complete bonding of the blocks together. Asshown in FIG. 8, the bonding cement is illustrated in adjacent coaxialcountersinks as represented by the numeral 51 between adjacent surfacesof blocks 48 and 49.

Preparatory to attaching the butt cap M to the threaded end 28 of thehandle tang 27, the threads of the handle tang are liberally coated withepoxy cement. The covered threads are then inserted into the threadedrecess 50. The butt cap 14 is then screwed on the threaded end 28 of thehandle tang and suitably tightened. The tightening action compresses themicarta blocks further to ensure their bonding together. The cement isthen dried for approximately 24 hours so that the micarta blocks willnot separate and they become an integral piece constituting the handle.

Next, an emory wheel is applied to the handle and butt cap where themicarta blocks and butt cap are ground to a desired shape. After therough shape has been achieved, a sanding wheel is applied where thehandle and butt cap are sanded and resanded using various grits ofsuitable resin bonded cloth. When this process is completed, a'perfectlyshaped smooth handle and butt cap is produced, such as is shown in FIGS.9 and 10.

The final step in the construction of the knife of the present inventionprovides for the final hollow grinding of the blade blank 22 which againrequires the use of a grinding means such as an emory wheel, forexample. Since the blade will heat fairly rapidly under grinding, thuslosing its temper, extreme care must be exercised to avoid prolongedgrinding. The finished grinding is a slow process as the blade must beconstantly cooled. The blade is hollow ground into 98 percent of itsfinal form during this final grinding procedure and from the emorywheel, the blade is taken to the sanding wheel where it is smoothed andall scratches are removed. Various degrees of grit cloth may be usedwith the last being of a grade of 320 grit. Preferably, this grit clothis graded immediately under the grade of polish per se. Next, finalbeautification of the knife is achieved with a soft cloth polishingwheel.

All that remains now is the final 2 percent of the hollow grindingprocess which is represented by the sharpening of the blade. The edgeand 18 are formed in a careful operation since, when it is complete,razor sharp edges are provided which are fully capable of shaving aheavy beard or skinning several animals without resharpening For storagepurposes, a thin film of oil may be placed on all exposed polishedsurfaces of the knife construction.

From the foregoing, it can be seen that the novel knife construction ofthe present invention and method provides a joint at the point of theblade base with the hilt and handle tang which is integral, having anonporous characteristic and which bonds materials of differentcomposition together. Such a joint is resistive to corrosive action andis capable of withstanding heavy stress under abnormal loadingconditions during use.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art thatchanges and modifications may be made without departing from thisinvention in its broader aspects, and, therefore, the aim in theappended claims is to cover all such changes and modifications as fallwithin the true spirit and scope of this invention.

1 claim: ll. A method of fabricating a knife construction comprising thesteps of:

joining a handle tang with a blade blank by welding adjacent endstogether to form an integral union therebetween; brazing the forwardface of a hilt mounted on the handle tang to the blade blank and to saidintegral union using bronze material; and brazing the rear face of thehilt to the handle tang using silver material wherein said integralunion and said brazed unions therewith provide an integral unitaryconstruction. 2. The method as defined in claim 1 including the step ofgrinding said integral union to provide opposite tapered sides leadingfrom the handle tang t0 the blade blank; and grinding the blade blankalong selected peripheral edges to form a cutting edge. 3. The method asdefined in claim 2 including the step of heating the blade blank with anacetylene torch to approximately l400 F. so as to temper the blade blankprior to said grinding thereof to form the cutting edge. 4. The methodas defined in claim 3 including the step of cooling said tempered bladeblank after said heating thereof in a bath of quenching oil followed byadditional heating in an electric oven slowly brought to a temperatureof approximatelv 450 thermostatically and subsequently being allowed tocool at ambient temperaturc. 5. The method as defined in claim 4including securing micarta blocks on the handle tang adjacent the rearface of the hilt followed by shaping said secured blocks to a desiredconfiguration and then sharpening said formed cutting edge.

1. A method of fabricating a knife construction comprising the steps of:joining a handle tang with a blade blank by welding adjacent endstogether to form an integral union therebetween; brazing the forwardface of a hilt mounted on the handle tang to the blade blank and to saidintegral union using bronze material; and brazing the rear face of thehilt to the handle tang using silver material wherEin said integralunion and said brazed unions therewith provide an integral unitaryconstruction.
 2. The method as defined in claim 1 including the step ofgrinding said integral union to provide opposite tapered sides leadingfrom the handle tang to the blade blank; and grinding the blade blankalong selected peripheral edges to form a cutting edge.
 3. The method asdefined in claim 2 including the step of heating the blade blank with anacetylene torch to approximately 1400* F. so as to temper the bladeblank prior to said grinding thereof to form the cutting edge.
 4. Themethod as defined in claim 3 including the step of cooling said temperedblade blank after said heating thereof in a bath of quenching oilfollowed by additional heating in an electric oven slowly brought to atemperature of approximately 450* thermostatically and subsequentlybeing allowed to cool at ambient temperature.
 5. The method as definedin claim 4 including securing micarta blocks on the handle tang adjacentthe rear face of the hilt followed by shaping said secured blocks to adesired configuration and then sharpening said formed cutting edge.